Flexible dies for bending thin metal plates in the direction of their width



@CTL 9 1923.;

R. 3. SMITH FLEXIBLE DIES FOR BENDING THIN METAL PLATES IN THE DIRECTION OF THEIR WIDTH Filed Sept. 12, 1921 W52 i? 6.55. w

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Patented @ct. 9, 1923.,

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REUBEN STANLEY SMITH, OF MILWAUKEE, WISCONSIN, ASSIGNOR, BY MESNE-AS-. v

SIGNMENTS, T0 FIRST WISCONSIN TRUST COMPANY, TRUSTEE, A CORPORATION OI N EW YORK.

FLEXIBLE DIES FOB BENDING THIN METAL PLATES IN THE DIRECTION 01* THE]:

WIDTH.

Application filed September 12, 1921. Serial No. 500,019.

To all whom it may concern:

Be it known that I, REUBEN STANLEY SMITH, a citizen of the United States, and a resident of the city of Milwaukee, county of Milwaukee, and State of Wisconsin, have invented a certain new and useful Improvement in Flexible Dies for Bending Thin Metal Plates in the Direction of Their Width; and I do declare the following to be a clear, exact, and complete description of the invention, such as will enable persons skilled in the art to which it relates to make and use the same, reference being had to the accompanying drawing for an exposition of the details of one constructional form in which ll have chosen to embody my said invention. 7

In Patent No. 1,466,104 granted August 28, 1928, on an application, Serial No. 367,799, filed on March 22, 1920, by Henry Miller, Frederick Orton and me, as joint inventors, there is disclosed a press for ofisetting, or bending edgewise, thin rectangular metal plates, so as to distort the side lines thereof and increase the' superficial area of the plate 'to such an extent that a curved blank, much wider in its extended proportions than the rectangular plate, can be pu'nchedggtherefrom, without the unavoidable and expensive waste of material attending the practice of methods heretofore in vogue.

The press disclosed in the application just referred to, is provided with a bed and a drawing head, which latter reciprocates in a path extending transversely of the bed. Both the bed and the head of the press are equipped with specially designed, contoured, complemental dies, which act respectively upon the opposite edges of the blank, the

pressure exerted by th' fixed dies carried by the reciprocating head and acting upon one edge of the blank being resisted by the pressure exerted against the other edge of the blank by the relatively stationary dies fixed in the bed of the press. As a result of the pressures thus opposed, in the approach of the dies toward each other, the blank of rectangular form is converted into one of curved or irregular form, and the outlines of which are made to conform closely to the pre-arranged curved lines of the complemental sets of dies carried by the press.

In order that the wide plate may not buckle when pressure is applied to the edges thereof, as described, it is necessary to exert a confining pressure upon the sides of the plate,'so that the flow, or displacement of the metal, may occur only in the directions desired. This result is attained by means of mechanism disclosed in the application hereinbefore referred to.

Serious problems are involved in the production of dies suitable for use .in plate bending presses of the type referred to, and their manufacture is attended with difliculties. Dies in lengthy sections, and integral die members, are diificult to temper properly without warping, and are subject to fracture by reason of the inability to apply the pressures exerted in the operation of the press upon all parts of the die at the same instant. A broken die of this character involves considerable loss, with a corresponding expense in effecting its replacement. Again, separate dies in lengthy sections, and integral die members, are required to be made for work in which theoutlines differ from one another, with a consequent added cost for the productionand maintenance of the several different forms or kinds of dies.

The very serious objections adverted to as inhering in the former system of die production, are eliminated by my invention, in which I provide a system of interchangeable dies constructed as units, which may be multiplied as required by the design of any particular work which it may be desired. to produce. My invention provides a system of dies in which there exists the greatest degree of flexibility, thereby permitting the die units to be assembled and arranged in the press in accordance with the work which it may be desired to produce. The die units being of small dimensions, are easily secured in position .in the press, and may be removed or changed with equal facility. Their separate production is most economically effected. v

The die units manufactured in accordance with my invention may be provided with straight, angular or curved acting faces, designed in a complete set to meet the demands of a wide range of work. With a stock of such dies, it is comparatively a simple matter to equip the bending press with complemental sets of dies, selected with.

a view to the production of work of desired contour.

Patent No. 1,340,138, granted to Henry Miller, on May 11, 1920, and Patent No. 1,452,255, granted to me on April 17, 1923, disclose the idea of thickening the plate in certain areas, so as to provide an integral reinforcement, to resist breaking strains in the narrower portions of the automobile side bar or other article produced from the blank, after the latter has been cut from the plate. In practice, the reinforcement described is reduced by the edgewise compression o the plate in certain sections with a resultant thickening of the same in the areas of compression. To permit the cross fiow of the metal in effecting the compression, the die units used in the press to attain the desired result will be provided with a slight clearance to permit the necessary expansion or increase in the gage of the metal.

The features residing in the invention will now be described in detail, and the novelty thereof will be pointed out in the appended claims.

In the drawing which accompanies this specification,

Figure 1 is a plan view of a set c0mprising upper and lower die members constructed in accordance with my invention, the upper die member being broken away for a portion of its length so as to show the contour of the die units of the lower die member, and a rectangular metal strip as in position between the die members to have an ed ewise bending pressure applied thereto. ig. 2 is a similar plan view showing the die members as having completed their approach to each other, and the rectangular strip converted into one of curved or irregular-form, with the ends thereof somewhat narrowed bythe compression exerted in the bending operation.

Fig. 3 is an end view looking from the left of Fig. 1.

Fig. 4 is a view looking from the left of Fig. 2, and showing how the metallic strip isreinforoed by an increase in thickness due to compression.

Fig. 5 is a cross-sectional view, it may be at any point in the length of the dies where compression and expansion do not occur, but in the present instance, on the line 55, Fig. 2, looking in the direction of the arrow.

Fig. 6 is a diagrammatic plan View, similar to Fig. 1, but showing the action of the dies in imparting an edgewise bend to the metallic strip without curving the same. F Fig. 7 is a view looking from the left of In the drawing, the numeral 10 indicates the upper and the numeral 11 the lower of a pair of bending die members constituting a complemental set, designed for use in the presses hereinbefore referred to. Each member of the set is composed of a plurality of interchangeable units 12, which are adapted to be assembled and secured in proper positions in the movable head and fixed bed, 'respectively, of the press, so that the acting faces of the units comprising the complemental set of dies will oppose each other.

The die units are rectangular plates of hardened steel, and are cut away for a portion of their length to form a transversely ex-.

tending shoulder 13, which latter constitutes the acting face of the die which bears against the edge of the rectangular plate 14, when the bending pressure is applied to;

the latter.

The acting faces 13 of the die units may be formed on' any lines desired,-either curved,

angular or straight,as may be necessary to produce the predetermined contour in the side or edge lines of the plate, and will-be the gage of the metal plate which is to be.'

bent. The said lower planesurfaces 16, of the complemental die members, are designed to act with .a confining pressure upon the sides of the plate 14, when bending pressure is applied to the edges thereof, so as to resist the tendency of the thin metal plate to buckle in the movement of the dies over each other, and thus preserve the 'planiform condition of the metal plate throughout its area.

Relative movement of the die members with respect to each other, as described, will convert the rectangular plate 14 shown in Fig. 1, into the curved plate 17 shown in Fig. 2. The comparative increase thus produced in the width of the plate, will enable'a'curved blank having a corresponding extreme width to be cut or blanked therefrom, with but a relatively small proportion of waste, and effeet a saving of approximately 50% in the material used over the present practice of punching a curved blank from a rectangular plate having a width sufficient to accommodate the extreme width of the curved blank.

The plate 14 will be positioned upon the ing face 13 of the lower die member,- which i is held immovably in the fixed bed of the press. The upper side and other edge of has a sliding engagement with the 'lower plane surface 16 of the opposite die member,

beyond the edges of the metal plate, in the lower plane surface 16 and against the actmesa ' movement of the dies under thebending pressure. r

The curved drawn into a channel tot'orm the side bar of "an, automobile frame,- such side bar in it's ends,

position of use, having a vertical web and flanges, extending laterally from the upper and lower edges thereof, as usual. In such a construction, the side bar tapers at its junctive parts of the automobile, and the reduction in the Width of the web at these ends has a tendency to weaken the side bar" at the points mentioned.

To impart the necessary degree of rigidity to the side bar, and avoid the necessity for the employment ofreinforcing attachments of any kind, ll propose, in some instances,

to form upon the narrower portionsot the 2@ side bar an integral reinforcement, which is produced by increasing the gage of the metal in the narrower parts of'theblank from which the sidebar is drawn. This result, as hereinbefore stated, is achieved by thickeningthe metal in the desired areas flow laterally with relation to the width of the plate and into the clearance' space's provided in the die units, and .thus produce an integral reinforcement of the plate in the areas desired.

The manner in which the result described is attained, will be apparent from an inspection of Figs. 3 and l, and comparison with Fig. 5. The first named views show the deepened acting forces 18 of the die units,

while that last mentioned shows the acting 59 which are designed to exert compression to J 18 of the compression die units, soithat such plate is desired without bending, the die faces 13 of the die units as of normal depth and not designed to exert compression. The thickened plate is indicated at 19, in Fig. 4; It will be understood that the die units efi'ect the thickening ofthe plate in the desired areas, are caused to approach each -other more closely than vdo the die-.iunits whose function is limited to the exertion of bending pressure against the edge of the plate... Such approach is cfiected byadvancing the relative position of theacting faces faces in the complemental set have less than the normal separation. The integral reinforcement ofcertain areas of the plate may be produced by deepening the acting face of the complemerital reinforcement only of certain areas of the blank 17a, intended a be.

to'accommodate the attachment of adfor engaging \die numbers, and where units in the complemental set'will have their acting faces so formed and arranged in the press as to effect this result.

In some classes at work, it is necessary only to effect a simple edgewise bending of the plate, without curving, to adapt it to its intended purposes. Such a bend may be produced by arranging selected die units in the press at separate points with relation to the opposite sides ofthe plate, in the manher indicated in Fig. 6, wherein die units 20, carried by the transversely moving head of the'press, are opposed by a die unit 21,

mounted upon thefixed bed of the press, the

respective units being staggered or alternated as shown. I

With a complete equipment shaped die units, therefrom to adapt tion of blanks of any desired outline, inasof properly selection may be made much as such an equipment will cover alarge range of variety in the work. Once acquired, such a stock of die units will eliminate the necessity for'themaking of other die units whenlthe character of the work is to be changed, or it is desired to produce a particular job; and itwill be necessary. only the press to the produc--.

to select appropriate dies from those already I in stock, and set up the press in conformance wlth the requirements of the new work.

Having thus described myinvention, What I claim and desire to secure by Letters Patent of the United States, is:

1. The combination of a pair of'co-acting flexible dies for bending metal plates in the direction of their width, each or the dies of the pair comprising a set of interchange i able die units arranged respectively to bear against the edges of the plate to exert a bending pressure and upon the sides of the plate'to exert a clamping pressure.

2. The combination of a pair of co-acting flexible diesfor imparting an edgewise bend to a Wide metal .plate, comprisingcomplemental die members, each of the pair com-- posed of a set of separate die units having their acting faces formed to bear upon the edges of the plate at points staggered or alternated with relation to each other, and to bear upon the sides of the plate toprevent buckling during the bending operation.

3. A plate bending die member comprising die units in mult1ple, each unit of which die member is formed with an actingiace operation, in combination with a die member engaging the other edge and side of the plate in such operatiom 4.] A plate bending die member'adapted to change the @ntour of the edge of a thin metal plate having a width greatly in ex cess of its thickness, the said die member one edge of the plate for a bending operation and a plane surface for engaging one side of the plate to prevent buckling of the plate during such bending being composed of an assembly of interserve the gage changeable die units each of which has an edge engaging gage of the metal plate to be bent, and aplane surface to engage the side of,the plate to prevent b uckling in the bending operation, in combination With a die member engaging the other edge and side of the plate bend to a thin metal plate, a complemental 7 set of die members, such members being each composed of a plurality of die' units provided with an edge engaging face and a plane surface extending therefrom, with said rality of die units each of which has an act ing face for engaging the edge of the plate and a plane surface to engage the sides thereof, the said plane surfaces lying in differface of approximately the areas toproduce an .when pressure is applied to plane surfaces of said units lying in different planes in some of the dies to perent planesin some, ofthe die units, to pre;

and to permit expansion of the gage in other integral reinforcement, the edges, of the plate, in combination with a die member engaging the -other edge and side of the plate. a p

7. In a sheet metal working'pres's, complemental die members each composed of interchangeable die units grovided with an acting face for engaging the edge of a metal plate and. plane surfaces normally out-of engagementwith the-sides of the plate" but adapted to contact therewith, in the expansion of the plate under compression applied by the die unitsvagainst the edges thereof.

In testimony whereof, 1 have-signed my name at Milwaukee, this 7th day of Septemher 1921. I

' R STANLEY SMITH..

Witnesses:

W. F. Woomnn,

EMMA HANG.

of the plate as certain areas .i 

